GANDAMAN/NEW DELHI, India -- Indian police suspect that India's worst outbreak of mass food poisoning in years was caused by cooking oil that had been kept in a container previously used to store pesticide, the magistrate overseeing the investigation said on Friday.
Health officials in the eastern state of Bihar were due on Friday to release autopsy results for many of the 23 schoolchildren who died on Tuesday after vomiting and convulsing with agonizing stomach cramps.
The children fell ill within minutes after eating a lunch provided by their school in the village of Gandaman. The free meals are part of a national scheme aimed at tackling malnutrition and encouraging children to attend school.
"Circumstantial evidence suggests that cooking oil was kept in a container which was previously used to store pesticides or insecticides," Abhijit Sinha, district magistrate of Saran district, said by telephone. Gandaman is in Saran district.
"At the moment we cannot say whether it was deliberate or it was pure negligence," he said, adding that police were searching for the headmistress of the school.
He said forensic tests were being conducted on the mustard oil container, uneaten food and utensils to determine the cause of the poisoning.
Reuters reporters saw police and local officials raid the headmistress's home in Gandaman on Friday while residents crowded outside.
One of the officials said it was the second such search of the house. In the first raid, police removed a 2-litre (68 U.S. fluid ounce) plastic container of mustard oil, a sack of rice, a bag of lentils, salt and spices. He would not say what more they were looking for on Friday.
It is not yet clear where the headmistress bought the food for the free meals, cooked at a makeshift kitchen outside the one-room ramshackle school. Police said she left the village on Tuesday with her husband, a local businessman who owned a shopping complex of about 40 stores.
At the local police station, some of the pots and pans from the school kitchen were piled in a corner.
An empty bottle of mustard oil lay on top. A local policeman, Ashok Kumar, said the headmistress had decanted oil from the 2-litre container into the bottle for daily use in the kitchen as there was no storage space at the school.
Doctors treating some two dozen children at the main hospital in Patna, the capital of Bihar, have said they suspect the children were poisoned by organophosphorous, a compound used in pesticide.
"The minute the children were brought in, we smelled this foul odor of organophosphorus," said Dr. Vinod Mishra.
The children fell ill, along with the cook, after eating a meal of rice and soybean-potato curry.
Although there have been widespread complaints of food quality in the Mid-Day Meal Scheme in India, the world's largest school feeding program, cases of mass food poisoning are rare.
In 1998, adulterated rapeseed oil killed as many as 60 people in the capital New Delhi. Investigations later revealed that the oil had been mixed with white oil, a petroleum product.